1. Technical Field
The present disclosure generally relates to optical devices, and particularly to an optical lens and a light source module which has the optical lens.
2. Description of Related Art
In recent years, thanks to excellent light quality and high luminous efficiency, light emitting diodes (LEDs) have increasingly been used as substitutes for incandescent bulbs, compact fluorescent lamps and fluorescent tubes as light sources of illumination devices.
Generally, a conventional light source module includes a lens covered on the light source to adjust an angular distribution of the light radiated from the light source. A conventional lens includes two curved surfaces, a small curved surface adjacent to the light source and a big curved surface away from the light source. The big curved surface covers the small curved surface therein. A bottom surface connects bottoms of the big curved surface and the small surface. The bottom surface is flattened. However, part of light passing in the lens strikes on the bottom surface and is reflected to some regular directions, which results in a small light field.
Therefore, it is necessary to provide an optical lens and a light source module to overcome the above-mentioned shortcomings.